DESCRIPTION: (provided by the applicant) This study is designed to investigate the relationship between nicotine intake, attention allocation, and anxious responding in heavy smokers diagnosed with chronic posttraumatic stress disorder (PTSD). Although there is much work on the effect of nicotine on affective responding in the general population, there is a paucity of such research on certain classes of psychiatric disorder that are characterized by high levels of anxiety. Such research is needed as several lines of investigation suggest that individuals diagnosed with PTSD evince rates of smoking more than twice that seen in the general population. They are also at risk for poorer health outcomes relative to comparable groups of non-PTSD individuals, possibly due to the comorbidity of poor health habits such as smoking. There is little research however, that attempts to understand the mechanisms by which smoking becomes so prevalent in this population. Current affect regulation models of nicotine have the potential to inform our understanding of the high comorbidity between smoking and this common psychiatric condition; however, research on the issue remains absent. To address this gap in the literature, the current study is proposing to examine the relationship between nicotine intake, attention allocation, and anxious responding in heavy smokers diagnosed with chronic PTSD. Utilizing a factorial design, heavy smokers with PTSD will be randomized to undergo either a neutral laboratory procedure or one known to elicit conditioned anxious arousal. Subsequent to the laboratory mood induction, subjects will smoke either high yield nicotine cigarettes or placebo (nicotine free) cigarettes prior to being randomized to either an attention allocation task or no task condition. Concurrent measures of autonomic reactivity (heart rate, skin conductance, and blood pressure) and self-report will be gathered as indices of anxious arousal elicited by study experimental conditions. Hypotheses regarding the manner in which nicotine interacts with attention allocation to environmental stimuli to bring about either anxiolytic or anxiogenic effects will be tested from the perspective of the theoretical model of nicotine.